You should also check to see if your contractor offers other services related to carpets. I.e. carpet cleaning. This will show you the degree of diversity you are working with and can help you kill two birds with one stone. However, you shouldn't ignore a candidate just because he specialized in only one field. You should look at the quality services that he or she offers. Do they offer to pay back their fee if something goes wrong?
License and certification
Make sure that you are working with a qualified and certified contractor. This means that the person you've hired has undergone the necessary training needed to do a good job for you. Remember that most certified and licensed contractors have a good reputation for behavior since a background check is often done on them before they are issued the certification.